Alfredo diatto



(No Model.) 2 Sheetssheet 1.

A. DIATTO.

ELECTRIC TRAMWAY WITH UNDERGROUND DISTRIBUTION OF CURRENT. N0. 550,319.Patented Nov. 26, v1895.

IQ w u wg I g .g E gw w u l HHI Q WITNESSES:

ATTORNEY ANUREW B GRAHAM Primo LWMILWASMNGYDMDC (NIO Model.) 2Sheets-Sheet 2.

A. D-IATTO. BLBGTRIG TRAMWAY WITH UNDERGROUND DISTRIBUTION 0I' CURRENT.No. 550,319. Patented Nov. 26,1895;`-

@75' lnmlmsmn inmif//A I I f INVENTOR ATTORN EY UNITED STATES PATENTOFFICE.

ALFREDO DIATTO,'OF TURIN, ITALY.

ELECTRIC TRAMWAY WITH UNDERGROUND DISTRIBUTION 0F CURRENT.

SPECIFICATION forming part of Letters Patent No. 550,319, dated November26, 1895.

Application filed September 18, 1894. Serial No. 523,410. (No model.)

To all whom, it may concern:

Be it known that I, ALFREDO Dnirro, a subject of the King of Italy,residing at l2 Piazzo Gran Madre di Dio, Turin, Italy, have inventedcertain new and useful Improvements in Electric Tramways withUnderground Distribution of Current, of which the following is aspecication.

This invention relates to an electric tramway wherein each car orcarriage is equipped with means for receiving the electric currentthrough magnetic induction from a source of underground distribution bysliding over contact-pieces located at suitable intervals over a subwayand suitably insulated and extending slightly above the surroundingsurface of the ground, such contact-pieces being adapted through themedium of suitable circuit-closing devices beneath the same and withinthe subwayT to be placed in communication with the electric cable in thesubway simultaneously with the passage of the car or carriage over suolicontact-pieces, the said circuitclosing devices being inclosed within acasin g constituting a part of the subway.

A leading feature of this invention is that the magnetic induction isproduced through a bar polarized north or south for its whole length,whichlength is about that of the car or carriage and greater than thedistance between two successive contact points and adapted to be broughtin contact with a softiron switcheblocl; communicating with theunderground conductor, the said switch-block being attracted byaforesaid contact-pieces as the polarized bar on the carriage slidesover them,`the said switch-block falling back into its resting-place asthe car or carriage passes by and in consequence of the magnetic actionof the bar ceasing.

The attraction of the soft-iron switch-block by the contact-piece can befacilitated by establishing communication between it and the undergroundcable through a body of mercury, a part of which the switch-blockdisplaces during its normal position of repose, the weight of that partof the mercury thus displaced being about equal to the weight of theswitch-block. The weight of the switclr block is thus reduced to aminimum at the moment of attraction, and when attracted to the point ofcontact it displaces very little mercury, in consequence of which factthe switch-block having regained nearly all of its weight more readilyreturns to its position of repose.

Important objects of the invention are to assure the breaking of thecurrent upon the happening of an accident of any description, to reduceto a minimum the number of insulated points, the amount of insulatingmaterial required, and the number of points at which the current is fed,and to reduce the cost of installation.

The technical advantages appertaining to my improvements will appearfrom a consideration of the following description.

In the accompanying drawings,which form a part of this specification,and wherein like parts are indicated by like letters of reference,Figure l represents, diagrammatically, the general arrangement of asystem Aembodying my invention. Fig. 2 is a vertical cross-section ofthe switching mechanism and of the casing inclosing the same. Fig. 3 isa fragmentary sectional view, on an enlarged scale, of the switch-blockor circuiteclosing device and means for connecting the cables K K to thereservoir containing the mercury. Fig. 4 is a detail sectional view onthe line 3 3 of Fig. 3. Fig. 5 is a detail sectional view through thecoupling-piece f at right angles to Fig. 3. Fig. 6 is a top plan view ofthe coupling-piece f. Fig. 7 is a top plan view of the means forconnecting the cables to the coupling-piece f; and Fig. 8 is a verticalsectional view, on an enlarged scale, of the switchblock in its normalcondition of repose and of the connection between it and the undergroundcable, the said view also showing in elevation a fragment of the postdepending from the contact-piece.

Referring to the drawings, S indicates the rails; K, the undergroundVconductor for the electric current; A A A2 A3 A, a series of contacts ordevices for feeding the current, one of which being shown on an enlargedscale in section in Fig. 2.

G indicates the dynamo for supplying the current, E an electromotor, andM the electromagnets by which the bar a is magnetized. Theelectromagnets M, the number and position of which may be varied, areexcited by a shunt or block circuit7 and they all im IOO part to the bara polarization of the s ame nature. The electromagnets M form, togetherwith the bar a and the auxiliary bar l, a truss, which is adapted to belocated conveniently under a car or carriage and carried thereby and tobe insulated therefrom.

The switching mechanism is inclosed in the casing p, which is preferablyround and beneath which is located the conduit for the electric cable K,as shown in Fig. 2. A part of the top casing is composed of soft ironand is indicated by ZJ, and it serves as a contactpiece and as a mediumthrough which the magnetic .forces attract the circuit-closing device d,which I otherwise term a switch-block. The contact-plate b projectsabove the ground sufiiciently to permit of proper and suitable slidingcontact of the polarized bar a, which serves to collect the current. Thecontactplate h is provided with a post or projection on its undersurface, which attracts the circuit-closing device or switch-block d, aspresently explained; The contact plate or piece b is insulatedmagnetically and electrically with reference to the cast-metal casing pby means of suitably-prepared wooden blocks 7L and strips of pure rubberg/, all as shown in Fig'. 2. The wooden blocks 7L rest upon the casingp, as shown in Fig. 2, and are held in place by the pressure of thecover or contact plate b, which latter is secured in place by posts lr,connected to the contact-piece b and to an insulated stirrup co-operating with the wooden sleeper b2.

The connection between the coupling-piece f and the cables K K isillustrated in Figs. 3

to 5, in which p indicates a plate resting on the bottom of the casing pand secured in place by the screw-bolts and lock-nuts p2 p3. Through thecenter of plate p passes the cables K K, the ends of which are securedWithin the screw-threaded openings of the split base of thecoupling-piece f by the bolt and nut f f2, as shown in Fig. 5. Thispiece f, Figs. 2 and 3, serves to unite the wires of the cables K K andalso as the feeder for the current. Its upper end is made of conicalform, which is adapted to receive the lower end of a reservoir c,containing mercury q, into which the circuit-closing device d is adaptedto dip. The mercury-inclosure and the mercury are used to form anelectric connection between the coupling-piecef and the circuit-closingdevice d, and the connection is made between circuit-closer d and theprojection c by magnetic adherence when the bar c slides overcontact-plate b, and when this occurs the current is from cable K tocoupling f, reservoir e, mercury q, circuit-closer d, projection c, tocontact-plate b.

The attraction of the switch-block or circuit-closing device d by thecontact-plate h is effected, owing to the fact that as the magnetizedbar a slides over contact-piece h there is produced at the end of itspost or projection c a pole of the same nature yas that in the bar a.The contact-surfaces of the projection c and switch-block d arecarefully galvanized, or instead thereof they may be plain surfacescapable of magnetic adherents, with mercury inclosure and depending uponthe movement of switch-block d.

The circuit-closing mechanism is all within the casing p, and theatmosphere is the only insulating material.

It will be seen that the switch-block d is attracted by thecontact-piece b only while the bar a is in sliding contact with saidcontactpiece, and that the switch-block falls back into itsresting-place when the car carrying the magnetized bar passes beyond theparticular contact-piece and thus uncovers it. The contact pieces orplates are arranged uniform distances apart, and the distance issomething less than the length of the bar a,

so that in operation the circuit is always closed, but only through themedium of that particular contact-plate that is for the time beingcovered and protected by the car or carriage.

If, owing to any possible accident, any carriage should come to a stop,the same would be promptly set in motion again by placing upon thecontact-plate b of one of the casings p a permanent magnet of sufticientforce and of the same character'as magnets M, the circuit-closing deviced within the casing will be attracted to the projection c, and thecontactplate b will then become active and an electrical connection willbe formed between the contact-plate b and the bar d of the car, thusexciting electromagnets M of the car, and thereby establishing anelectric current between said magnets and the underground cables. Bymeans of these temporary connections any one of the parts involved canbe readily exchanged without stopping the travel of the carriages on theline.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent of the United States, is-

l. The combination with a conduit inclos-` ing the underground conductoror conductors, a series of contact plates or pieces in the top` of saidconduit and insulated from the ground and provided with projections ontheir inner surfaces, and circuit-closers comprising a bar of soft ironand a cylinder containing mercury, said circuit-closers communicatingwith the underground conductor, of electrical appliances supported on acar or carriage and including a magnetized bar which is adapted to glideover aforesaid contact plates or pieces and thus connect said plates orpieces with the underground conductor through magnetic induction fromthefcarri age, the aforesaid circuit-closers returningto the position ofrepose by their own weight when the magnetized bar completely uncoversthe contact plates, substantially as set forth.

2. The combination with an underground conductor, a series of contactplates in the top of the underground conduit and electrical appliancessupported on a car or carriage and IOC' iid

ing Within the mercury in said cylinder and a coupling piece, as f,serving to unite the Wires of the conducting cable and as a feeder 15for the current, substantially as set forth.

Signed at the consulate of the United States of America at Turin, Italy,this 22d day of August, 1894:. v -\n ALFREDO DIATTO.

Witnesses SENSO HELLos, RAFFAELE Rossa.

